2.  Separation of liquid substances according
to their
differing
boiling points.

3.  Fractionaldistillation:
separates parts of
petroleum into
mixtures called
fractions.
 Compounds in each
fraction have a range
of boiling points and
specific uses.

4.  Crude oil is composed
of MANY different
hydrocarbon
compounds
 The different
compounds have
different numbers of
carbon & hydrogen
 Essentially the “chain
gets longer”

5.  Smaller,lighter molecules have lower boiling
points and condense higher in the tower.
 Bigger,heavier molecules have higher boiling
points and condense lower in the tower.
 Label on your picture where the smaller
hydrocarbons will be collected and where the
larger hydrocarbons will be collected.

6.  Theattraction between molecules. Also
know as… BONDS!
 Smallhydrocarbons- weak intermolecular
forces so low boiling point
 Largehydrocarbons- stronger
intermolecular forces so higher boiling
point

7.  So as the chain gets longer, the boiling
point gets higher
 More intermolecular forces to break, so
more energy is needed to break them all!